The invention relates to laser surgery and in particular to apparatus which is sufficiently portable to enable manual manipulation of laser radiation in the performance of a surgical operation at a predetermined point or points in the choroid, retina or other internal areas of an afflicted eye.
Laser surgery to date within the eye has involved relatively bulky apparatus wherein a slit lamp is the surgeon's means of observing the fundus of the patient's eye, and the output of a laser is so folded onto the axis of slit-lamp observation as to focus a desired laser-beam spot at the fundus. This necessarily involves use of the focusing power of the eye, and a lens system in external contact with the cornea is employed to correct astigmatic and other refractive errors, so as to control fidelity and size of the laser-beam spot at the fundus. With such apparatus, the slit lamp is desk-mounted and the patient must sit upright, effectively clamping himself to the chin rest of the slit lamp, to assure his immobility. The slit lamp has certain degrees of aspect manipulation by the surgeon, and an auxiliary light source, such as the attenuated output of helium-neon laser is spliced into a collimated part of the laser-beam optical system (prior to folding into slit-lamp viewing axis), to provide a viewable spot which is the spot size of the laser beam relied upon for surgery; such an auxiliary light source and splicing are described in my copending application, Ser. No. 617,931, filed June 6, 1984.
Laser surgery to date within the eye has involved relatively bulky ruby, argon, krypton, neodymium-YAG, and organic dye lasers which, with conversion of light to heat energy, produce a thermal rise in tissue temperature sufficient to create a photocoagulation or coagulum. The pulsed neodymium-YAG laser, equally bulky, produces a moderate output power and short exposure which create high power densities; and the part of a body to be operated upon must be precisely positioned for the particular desired operation. Radiation wavelengths of the aforementioned lasers are in the visible or near-infrared portions of the spectrum and therefore local coagulation, vaporization, or disruption of tissue is a necessary consequent of the exposure. Careful alignment and assured fixation of the patient's eye are required, for each laser exposure. When the infirmity requires several exposures, as at different locations on the retina, the procedure is cumbersome and time-consuming, requiring great patient cooperation, and the apparatus is very expensive.
In my copending application Ser. No. 552,983, filed Nov. 17, 1983, I disclose laser apparatus and techniques for ophthalmological surgery wherein selective ablation of body cells is achieved by photodecomposition, without coagulation or vaporization, using radiation in near end and far portions of the ultraviolet end of the spectrum; and in my copending applications, Ser. No. 571,827, filed Jan. 19, 1984 and Ser. No. 617,931, filed June 6, 1984, I disclose further such apparatus having ophthalmological application, the device of Ser. No. 571,827 being a pencil-like manipulable tool with flexible optical-fiber cable connection to a local source of laser radiation, and the device of Ser. No. 617,931 being a scanning laser apparatus for non-invasively removing a cataractous lens. Reference is made to said applications for more complete discussion.